Process for controlling the development of reversible color film

ABSTRACT

PROCESS FOR CONTROLLING THE DEVELOPMENT OF MULTILAYER REVERSIBLE COLOR FILM WHICH HAS COMPONENTS INCORPORATED THEREIN CHARACTERIZED IN THAT THE FIRST DEVELOPER CONTAINS AMINOMERCAPTO DERIVATIVE HAVING 1 HETEROCYCLIC RING HAVING THE FOLLOWING FORMULA:   S=C&lt;(-N(-R)-C(=NH)-Y-NH-)   WHEREIN R IS A HYDROGEN OR ARYL AND Y IS AN ATOM OR ATOM GROUPING NECESSARY TO COMPLETE A 5 OR 6 MEMBERED RING, OR ITS CORRESPONDING TAUTOMER.

United States Patent O 3,597,199 PROCESS FOR CONTROLLING THE DEVELOP- MENT OF REVERSIBLE COLOR FILM Hans Glockner, Pullbach, Karl Kuifner and Herbert Stark, Munich, and Hans Gotthard, Leverkusen, Germany, assignors to Agfa-Gevaert Aktiengesellschaft, Leverkusen, Germany No Drawing. Filed Oct. 31, 1969, Ser. No. 873,115 Int. Cl. G03c 5/59, 7/00, 7/16 U.S. Cl. 96-22 7 Claims ABSTRACT OF THE DISCLOSURE Process for controlling the development of multilayer reversible color film which has components incorporated therein characterized in that the first developer contains an aminomercapto derivative having 1 heterocyclic ring having the following formula:

wherein R is hydrogen or aryl and Y is an atom or atom grouping necessary to complete a 5 or 6 membered ring, or its corresponding tautomer.

This invention relates to a process for controlling the development of multi-layered reversible color film having incorporated color components.

Color film according to the principal of chromogenic development consists essentially of 3 layers arranged one over the other, sensitized for the spectral ranges of blue, green and red and in which during color development dyes complementary in color to that of the sensitivity of the particular layers are developed. There is thereby obtained a color negative from which through a suitable copying process, a color positive is prepared. Using reversible color film, it has already become possible in a single process to obtain a finished positive.

This process consists essentially of the following steps:

(1) Development of a negative silver picture. In this case the first developer contains as developing agent for black-white, for instance, metol-hydroquinone.

(2) Development of a positive silver picture from the residual silver halide and simultaneously developing a positive color picture by the reaction of the developer oxidation product and a stored component. The developing agent of the color developer is a derivative of pphenylenediamine.

(3) Bleaching of all of the developed silver.

In color reversal development, it is often difiicult to maintain the process constant throughout, that is so that all 3 layers are always uniformly developed. Here it depends far-reachingly on obtaining the right color synchronization in the developing picture. This gives rise to the necessity of controlling the processing. One of the frequently encountered difiiculties is the phenomenon that the topmost layer, in general, the blue sensitive layer, which provides the yellow picture is developed too quickly. The reason for this lies in the swelling of Cir 3,597,199 Patented Aug. 3, 1971 ice the layers, in the diffusion of the developer chemicals, in the exhaustion of the developer as well as in the work ing of silver solvent medium, which results in the production of pure white in the first developer.

It is already known to slow down the over-development of the topmost layer or even of the top two layers. An agent heretofore used for the first developer has been small amounts of potassium iodide (DBP 968,447). Another procedure that has already been proposed is the addition of mercaptoazoles (DAS 1,003,581). Pat. 2,685,516 describes a combination of both of the aforesaid processes, i.e. to simultaneously add potassium iodide and mercapto compounds whereby it was found that both additions produce a much stronger effect would have been anticipated, i.e., a synergism (DAS 1,158,838).

The activity of the iodide and also of the mercapto compounds is to be traced to the fact that they are absorbed by the silver halide, thereby forming difficulty soluble silver compounds in the topmost layer and resulting in the slowing down of the development in that layer. Potassium iodide, as well as the aforementioned mercapto compounds have, however, detrimental effects so that their use as additives for accomplishing the above-described purposes is strongly limited. The detrimental effeot of the iodides lies in that they act on all 3 layers thereby lowering the total sensitivity of the film. The mercapto compounds, for instance, mercapto-tetrazole, -thiazole, -oxazole and -benzthiazole, thiohydantoin and the like and in particular 1-phenyl-5-mercapto-tetra- Zole have a strong tendency to form hazy or foggy color. This has been mentioned in the literature, for instance, in U.S. Pat. 2,725,290. The other mercaptoazoles have been found to be as unsatisfactory as phenylmercaptotetrazole. In addition the effect of most of the mercaptoazoles is too limited to prevent the over-development of the upper layer. A further disadvantage observed for the known compounds is that in their presence, the stability of the stock solutions is reduced. This is, for instance, the case with the otherwise well-working 5,5-dimethylrhodanine (DAS 1,158,838).

The object of the invention is to provide substances for controlling the reversible color development not having the disadvantages of the known materials.

In accordance with the invention, it has now been found that incorporating into the first developer an aminomercapto derivative constituting a one ring N-containing heterocyclic compound of the following formula or a corresponding tautomer thereof:

wherein R is hydrogen or aryl and Y is an atom or atom grouping necessary to complete a 5 or 6 membered ring which avoids the disadvantages of the art and results in considerable improvements in the development of reversible color film. Preferably Y is member selected from the group consisting of NR wherein R designates hydrogen or aryl and HC=CR' wherein R designates hydroxy or methyl.

N N H l-phenyl-5-an1ino-B-mercapto-1,2,4-triazole or its tautometers 4-oxy-6-amino-Z-mercaptopyrimidine HNIIIH C=NH III

or its tautometers 4-phenyl-5-amino-3-mercapto-1,2,4-triazo1e These compounds can be prepared by methods known from the literature. Compound I (which has been incorrectly designed in the literature as l-phenyl-3-amino-5- mercapto-1,2,4-triazole) is described and known from From, Baurnhauer, Annalen der Chernie 361, p. 336; compound II from Traube, Annalen der Chernie 331, p. 71 and German Patent 156,055 and Compound III by Arndt, Milde, Tschenscher, Chemisohe Berichte 55 pp. 344 and 354.

The following examples demonstrate the advantages associated with the use of the compounds as proposed in the instant application when added in suitable amounts generally 0.5 to 5 mg./l., preferably 1 to 2 m-g./l. to the first developer which is a known metol-hydroquinone or pyrazolidine-hydroquinone developer. The sensitivity of the underlying layers is not at all or only very slightly infiuenced. The compounds of the invention do not produce any color hazing. In addition their control effect is enhanced synergistically by the presence of potassium iodide.

The use of the aminomercapto derivatives in accordance with the invention allows for the preparation of stable storage solutions for instance in alcohol or aqueous alkali. Also the activity of the developer remains constant and does not vary. In general, the amounts of the aminomercapto derivatives which are to be added is very small in order to ensure that their effect is limited to the topmost layer. The amounts which are most advantageously used depend on the strength of the desired regulation and can be established in each case by experimentation.

The following example is given for the purpose of illustrating the invention and is not to be construed as in any way limiting the scope thereof.

EXAMPLE A three layer reversible color film strip in which the topmost layer is blue sensitive and which contains a color coupler for yellow was exposed behind a gray step tablet and thereafter subjected to the following color reversal processing:

Min. First development l2 Rinse 1 Fixing Bath (acetic acid/Na-acetate at pH=4.2) 5 Wash 5 Reversal exposure 1 Color development l5 Fixing bath 5 Wash 5 Bleaching (K-ferricyanide, K-bromi'de, pl-l=5.3) 8 Wash 5 Fixing (pH=5.0) 5 Final wash l0 Stabilizing (formalin and wetting agent) 1 Temperature of the baths, 24 C.

The first developer had the following composition:

Water ml 800 Sodiumhexametaphosphate g 2.0 p-N-monomethylamino phenolsemisulfate do 6.0 Anhydrous sodium sulfite g 50.0 Anhydrous soda g 35.0 Hydroquinone g 6.0 Sodium Thiocyanate g 15 Potassium bromide g 1.0 Potassium iodide mg 20 Water ml i000 pH value: 10 .1101.

The color developer had the following composition:

Water ml 800 Sodiurnhexametaphosphate g 2.0 Anhydrous sodium sulfite g 5.0 Trilsodium phosphate g 40.0 N,N-diethyl-ptoluylenediamine hydrochloride g 3.0 Potassium bromide g 0.5 Potassium iodide g 10.0 Ethylenediamine 50% ml 6.0

A second film strip was treated in the same manner and in the reversal developing process with the difference that the first developer contained 1 mg./l. of mercaptoaminoazole of Formula I. When the two strips were compared by measurements in a density meter using red, green and blue filters, it was observed that the second strip undoubtedly contained more yellow. The density of the other colors in the strip were not influenced by the differences in the first developer composition. This established that by the addition of compound I, only the sensitivity of the topmost layer was decreased. Further it could be observed that the clarity of the highlights is not in anywise influenced by the addition.

When the same experiment was repeated with 4 mg. phenylmercaptotetrazole in the first developer in place of compound I, there was obtained a color picture which against a 0 test had a 2 DIN lower sensitivity. If the amount of phenylmercaptotetrazole is lowered, the desired color control in the top layer is not observed. 0n the other hand, by an increase in the concentration, color fogging is produced. A similarly unsatisfactory result is obtained with the known mercaptobenzimidazole sulfonic acid ,(DAS 1,158,838). There substantially results in each case an unacceptable color fogging. When however compounds II and III in accordance with the invention are used excellent results are obtained, with the optimal amounts of about 2 mg./l. thereof in the first developer.

We claim:

1. In the process of color development for controlling the development of multi-layer reversible color film containing incorporated color couplers the improvement of incorporating into the first silver halide developer an aminomercapto derivative constituting a one ring heterocyclic of the following formula or a tautomer thereof:

tt S=C C=NH wherein R is hydrogen or aryl and Y is a member selected from the group consisting of -NR wherein R is hydrogen or aryl and HC=CR wherein R is hydroxy or methyl, necessary to complete a 5 or 6 membered ring.

2. Improvement according to claim 1 wherein said aminomercapto derivative is 1-pheny1-5-arnino-3-mercapto-1,2,4-triazole.

3. Improvement according to claim 1 wherein said aminomercapto derivative is 4-oxy-6-amino2-mercaptopyrimidine.

4. Improvement according to claim 1 wherein said first developer additionally contains potassium iodide an amount of 5-50 mg./l.

5. Improvement according to claim 1 wherein said References Cited UNITED STATES PATENTS 3/1964 Hunt 9622 8/1965 Schwan 96566 NORMAN G. TORCHIN, Primary Examiner M. F. KELLEY, Assistant Examiner US. Cl. X.R. 9655, 59, 66 

